Task 7 - fNIRS

Question 1

Name 5 Advantages of fNIRS

Answer 1

1. Non-invasive
2. Portable
3. Cheap
4. Integration with other techniques
5. Good compromise of spatial and temporal resolution

Question 2

Name 5 Limitations of fNIRS

Answer 2

1. Limited Spatial Resolution
2. Attenuation of light due to other sources
3. Impact of skin and hair pigmentation
4. Difficulty of obtaining baseline levels
5. Not yet well validated

Question 3

Why does fNIRS work?

Answer 3

Because hemoglobin has different optical properties depending on its oxygenation.

Question 4

What wavelengths are the near infrared spectrum used in fNIRS?

Answer 4

700 - 1000 nm

Question 5

What is the method of EROS based on?

Answer 5

Changes in the optical properties of the cell membranes themselves that occur as a function of the ionic fluxes during firing.

Question 6

What is the main similarity between fNIRS and fMRI?

Answer 6

Both are an indirect measure as they use deoxyHb as their marker for neural activity.

Question 7

Why is fNIRS more comfortable for the participant?

Answer 7

• It is quiet
• It can be used in any position and is not restrictive
• It does not have nausea inducing magnetic fields

Question 8

What is a major caveat of the spatial resolution of fNIRS?

Answer 8

That it only detects very superficial activity of a couple of mm deep into the cortex.

Question 9

When can a system be said to be a BCI?

Answer 9

When a machine is operated without the use of peripheral nerves or muscles.

Question 10

How do you call it when in BCI application, task performance is relayed back to the individual as sensory input?

Answer 10

Neurofeedback

Question 11

What ERP is often used for categorical decisions in BCI?

Answer 11

P3(00)

Question 12

What are the challenges of communicating with behaviorally unresponsive patients?

Answer 12

• Lack of a priori knowledge about their level of conscious awareness, cognitive capacities and their communicative intent
• Individual Differences
• Feedback is difficult due to limited sensory processing abilities.

Question 13

What are usual sampling rates for fNIRS?

Answer 13

~12.5Hz

Question 14

Although the temporal resolution of fNIRS is around .01 seconds, responses are measured with a delay of a couple of seconds. Why?

Answer 14

Because of the hemodynamic delay.

Question 15

What is an important software part of BCI that improves performance?

Answer 15

Machine learning algorithms

Question 16

What brain measure has been used most often for BCI?

Answer 16

EEG